The Caravella clone is a fully mechanical APV with Stainless Steel, and Brass construction.This is not a lightweight item. It is made with durability in mind, from the thickness of the metals, to the smoothness of the threading.The Caravella clone comes with a 510 threading for use with Most items that are 510 threaded.The threaded cap has airflow slots for proper airflow when flush mounting tanks. The center contact is also fully adjustable to compensate for different battery lengths. " Comes with 3 x different size center posts"The bottom firing cap features a reverse threaded lock ring. Compatible with Most 18350 sized batteries. The Caravella clone also comes with a replacement spring for the firing button. This is an advanced user device. As it is a fully mechanical device there is no built in protection circuitry. It does feature venting between the battery tube and switch assembly.(bateries and charger not included)